I've recently purchased a 2001 XJ8. At the time of purchase, the transmission showed no signs of life in any of the forward gears. The car would operate in reverse with no problems.
Just this morning I realized that the transmission will indeed engage in the forward gears (2, 3, 4, and Drive) after revving the engine to about 1,500 rpm.
I understand the valve body can be the culprit here. My questions are:
1. Can I replace just the valve body, and drive away happily?
2. Are the A and B clutches already at risk?
3. If I replace the valve body, and the car operates properly, is the transmission a time bomb, just waiting for the internal clutches to destroy themselves?
4. Should I just replace the entire transmission now with a properly rebuilt and upgraded transmission, and be done with it once and for all?
Thank you.

 

There are many better folks to answer this here, but to have to rev to 1500 to move forward, but reverse is working fine, could be a few things. Albeit yes, it could be the valve body, I also suspect the torque converter and/or pump. Does it shift surely when you get it going forward or does it slip between gears? Do you have torque when in gear or are you revving just to keep it going?
Have you done a search on any of these issues in the Search? I see RJ237 made a reasonable response, as did a couple others, to your previous post on the same issue before your purchase. Please keep your posts as one regarding the same issue because when you post in that thread again, they will get an email of the new post and probably look at. Now you don't know if someone like RJ237 may see this later to respond. Just an fyi....
Perhaps a Mod could join the 2 threads?

 

Dear Highhorse,
Thank you for responding. I'll check other threads for answers. I haven't driven the car at speed yet, this was just moving the car within my yard. The "Restricted Performance" light is on. I'm not sure if that is caused by the transmission problem?
Thanks again for responding.

 

The transmission could need fluid. Do a search for checking fluid level.

If that isn't the problem then it's time to remove the pan and see if there are a lot of chunks/ shavings on the magnets.

I would hesitate on spending the money to replace the valve body without at least taking the A drum out for inspection.

BobRoy, what is your opinion?

 

Mine was doing exactly the same and I had A-Drum failure

 

Ron Brooks,
POOP! I was hoping the tranny was not yet grenaded.
Thank you for the information.

 

+1. RJ.

Check oil level first.

If that doesn't cure it drop oil pan and look for pieces of metal. If you find pieces it will lean problem towards A drum. But if there isn't any pieces that doesn't rule out A drum. On my 99xk8 the A drum had failed but the outer ring that usally breaks off was still attached to the A drum so that no metal pieces had detached and fallen into the pan.

Just because the A drum might of failed doesn't mean the transmission has grenaded. It can be repaired. I generally followed the proceedure in the stickys. If you do it yourself it can be done for under $600, depending on extent of damage.

I repaired my wifes a xj8 over a year ago and she has put about 12,000 miles on it since then with no problems.

 

BobRoy,
Thank you for the information. I'll check the fluid level first. I remember seeing fluid on the underside of the bell housing when I winched the car onto the trailer to bring her home, wasn't sure if it was transmission fluid or engine oil. Either way, the leak needs to be diagnosed and remedied.
Are there any special tools needed for the rebuilding of the transmission?
Thank you.

 

Not any special tools. The only thing that I think you might have some trouble with, I did the first time, is removing and installing the cup , sorry I don't know the proper name of the part, at the bottom of the A drum. The first time I used C clamps and later made a tool to press it off and on. This needs to be removed from old A drum and installed on the new one.
When checking oil level follow the proper proceedure and try to get the car as level as possible.

 

I will probably get hammered for this but I bought the heavy duty A drum on ebay, pulled the tranny stood it on its tail pulled the front off changed out the drum put it back together and stuck it in the car. Drove it for a month when had timing chain failure. Bought this vdp with a bad tranny swapped them out and have put 1100 miles on it so far.